import matplotlib.pyplot as plt
from random import choice

class RandomWalk():
    def __init__(self, num_points=5000): 
        """初始化随机漫步的属性""" 
        self.num_points = num_points
        # 所有随机漫步都始于(0, 0) 
        self.x_values = [0] 
        self.y_values = [0]

    def fill_walk(self):
        """计算随机漫步包含的所有点"""
        # 不断漫步，直到列表达到指定的长度 
        while len(self.x_values) < self.num_points:
            # 决定前进方向以及沿这个方向前进的距离 
            x_direction = choice([1, -1]) 
            x_distance = choice([0, 1, 2, 3, 4]) 
            x_step = x_direction * x_distance
            y_direction = choice([1, -1]) 
            y_distance = choice([0, 1, 2, 3, 4]) 
            y_step = y_direction * y_distance
            # 拒绝原地踏步 
            if x_step == 0 and y_step == 0:
                continue
            # 计算下一个点的x和y值 
            next_x = self.x_values[-1] + x_step 
            next_y = self.y_values[-1] + y_step
            self.x_values.append(next_x) 
            self.y_values.append(next_y)

rw = RandomWalk() 
rw.fill_walk() 

#plt.scatter(rw.x_values, rw.y_values, s=15) 
#plt.show()

point_numbers = list(range(rw.num_points)) 
# 突出起点和终点
#plt.scatter(0, 0, c='green', edgecolors='none', s=100)
plt.scatter(rw.x_values, rw.y_values, c=point_numbers, cmap=plt.cm.Blues, edgecolor='none', s=15) 
# 隐藏坐标轴
#plt.axes().get_xaxis().set_visible(False) 
#plt.axes().get_yaxis().set_visible(False)
# 设置绘图窗口的尺寸 
#plt.figure(figsize=(10, 6))
plt.show()



